My answers are a bit slow here (still in moderation mode, might be for a while still). It does work at my end. I have no idea what David is trying, or why it isn't working. If you would like me to walk you through, I'd happily do that.

I did export an XML-file from FCPX 10.1. Imported it back in. Everything came through nicely. Apart from the settings on published parameters on my Motion templates. They were reset to the default values (=not included in the export). This is an issue, yes, but shouldn't be too damn icky for the apples to toss a fix together on that. Feels more like (again) something overlooked.